1. Field of the Invention
This invention relates to a sound effect-creating device used in electronic musical instruments and the like, and more particularly to a sound effect-creating device which is adapted to determine a predetermined reverberation time based on a repetition period of a timing clock of a MIDI signal, or vice versa, in imparting a reverberation effect to a musical tone.
2. Prior Art
In performance of a musical instrument or the singing of a song (hereinafter simply referred to as "the performance"), it is a known technique for making the performance, especially the chamber performance, sound natural, to impart to a musical tone a reverberation effect of increasing thickness and depth of the musical tone and adding reverberations thereto. To make use of this technique, a sound effect-creating device comprising a reverberator is generally used today, i.e., at the age of rapid progress in the art related to electronic musical instruments, thereby imparting the reverberation effect to the performance.
In imparting the reverberation effect to the performance by the use of such a sound effect-creating device, it is a conventional method that an operator of the sound effect-creating device sets a reverberation time to the reverberator based on the operator's sense, while taking into consideration the kind of a sound and the tempo of performance.
However, this method has the following inconveniences: First, it is naturally required to adjust, the reverberation time to the tempo of performance of an electronic musical instrument playing an accompaniment in imparting the reverberation effect to a tune played in the performance. Otherwise, reverberations of a musical tone produced by the reverberation processing of a signal of the musical tone do not agree with the accompaniment, and impedes the performance to the contrary. For example, if reverberation is performed on a lilting tune over a rather long reverberation time, the lilt of the tune played is lost. Therefore, the performance with a high tempo should be subjected to such reverberation processing as will suit the high tempo of the performance. According to the conventional method, however, it is difficult for an unskilled person to adjust the reverberation time to the tempo of performance. Moreover, since the reverberation time is set by the operator separately from or independently of the electronic musical instrument for the accompaniment, it prevents the tempo of the accompaniment of the electronic musical instrument from being correlated with the reverberation processing of the musical tone signal when the reverberation time is set to the reverberator. Furthermore, if the tempo of the performance or the accompaniment is changed during the performance, it is impossible to change setting of the reverberation time, since this will impede progress of the performance.